A variety of monitoring systems are implemented using different monitoring devices, such as cameras, motion sensors, keypads or contact sensors. For example, many buildings have multiple locations that are monitored for security purposes, requiring multiple monitoring devices in the different locations. For increased security and functionality, the monitoring devices can be configured to communicate with one or more central devices. The central device can, among other things, perform monitoring or recording functions, determine whether the security has been breached and whether to contact security personnel.
One method of communicating between the monitoring devices and the central device is by a physical connection, such as electrical or other wiring. Using wiring to establish communication between the security devices can be troublesome for a number of reasons, such as the high cost of installation and maintenance. For example, exposed wiring is often unacceptable in a building, and thus, the installation of the monitoring system requires passing the wires through the walls of the building. This type of installation can significantly increase the time required to complete a monitoring system installation. Moreover, the use of wires can limit the functionality of many monitoring systems, such as where it is desirable to have portable monitoring devices.
One potential solution is to use wireless monitoring devices to reduce or eliminate the need for physical connections between the devices, however, wireless monitoring systems also have a set of problems, such as battery life. Ideally, the security devices would be self-powered by, for example, a battery. Self-powered devices are more secure because they are not subject to failure upon a loss of power to the building. They also require less installation problems because they do not need to be connected to a separate power source; however, self-powered devices often have reliability issues due to the finite life of their power source. Increasing the useable time of a power source reduces the cost for replacement of the power source and increases the usefulness of the entire system by having less potential downtime of the system or its components. Several recent developments have increased the potential power requirements of wireless monitoring devices.
Another problem with power requirements arises from the desire to have increased monitoring capabilities with smaller devices. As monitoring systems become more advanced, the power requirements of the monitoring devices are often increased. For instance, monitoring devices that contain digital cameras require enough power to run the camera, to store the digital picture in memory and to transmit the digital picture to the central device. The increased functionality of the monitoring devices, along with the desire to have smaller, less noticeable devices with less room for batteries or other power sources, has impacted the reliability of the monitoring devices.
Attempts have been made to implement wireless security systems using a variety of methods. One such method is taught by European Patent Application Publication No. EP 1 363 260 filed on May 6, 2003, entitled “Procédé de communication radiofréquence entre plusieurs dispositifs et système de surveillance mettant en œuvre un tel procédé,” which is fully incorporated herein by reference. Yet, these methods still leave room for improvement.
These and other issues have presented challenges to the implementation of wireless communication devices, including those involving monitoring systems and similar applications.